Dental instrument



Oct. 20, 1953 J. DIENER 2,655,726.

DENTAL INSTRUMENT Filed Dec. 8, 1952 ATTORNEY Patented Oct. 20, 1953 UNITED STATES PATENT OFFICE DENTAL INSTRUMENT Jack Dicner, Washington, D. C.

Application December 8, 1952, Serial No. 324,746

(01. lift-d6) i 9 Claims.

The present invention relates to dental instruments and more particularly to a hand instrument particularly suited for trimming the gingival margin.

In the preparation of a tooth for an inlay, it is necessary to bevel the margin of the tooth at the gumline, or under the gumline, this portion of the tooth being known as the gingival margin. The gingival margin must be beveled to allow a greater seal at this portion of the restoration, to compensate for the gold shrinkage, and to allow a better finish to the restoration.

Heretofore, using conventional gingival marginal trimmers, there is a great deal of slipping caused. by the shape of the trimmers, resulting in the cutting edge slipping from the tooth into the gum causing trauma, and poor preparations due to the loss of vision caused by the resultant bleeding. Vision is poor in these areas in any case, and a sense of feel must be used, With conventional instruments for this purpose, it is almost impossible to obtain a definite width and depth to the bevel without the entire shoulder disappearing into a lay bevel.

It is therefore an object of the present invention to provide a dental instrument which may be used as a gingival marginal trimmer in such a manner that the danger of cutting into the gum i substantially reduced.

It is a further object of the present invention to provide a dental instrument which will trim the gingival margin of the tooth to yield a bevel of definite width and depth.

It is a still further object of the invention to provide an improved gingival marginal trimmer provided with a guiding surface that will permit beveling by a sense of feel without looking at the margin being worked on.

These and other objects of the invention are accomplished by providing a flat ledge along a portion of the applicator portion of the instrument to be seated on the tooth and serve as a guide for preventing slipping off of the instrument and permitting the operation of the instrument by a sense of feel.

Other objects and the nature and advantages of the instant invention will be apparent from the following description taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a side elevation of the instrument;

Fig. 2 is an enlarged detail of the applicator portion of the instrument;

Fig. 3 is an enlarged detail of the applicator portion of a modified form of the instrument;

Fig. 4 is a fragmentary view of a tooth which has been partially prepared for the inlay and a portion of the instrument showing the instrument in use;

3 Fig. 5 is a similar fragmentary View of a tooth and a portion of a conventional instrument of the ltype currently in use;

Fig. 6 is a similar fragmentary view of a tooth ishowing the bevel obtained by use of the present ,invention; and i Fig. 7 is a similar fragmentary view of a tooth showing the bevel obtained by use of conventional instruments of the type currently in use.

The instrument comprises a handle portion It which may be of cylindrical formation and may conveniently be provided with flat sides, as shown, a rounded end I I, and a tapered end portion H2. The tapered end portion l2 bends slightly at E3 to provide an angular extension l4 having a rounded bend joining it to the tapered portion I2. The angular extension I l again is bent in an opposite direction to form a rounded heel l5 terminatin in the applicator portion !6 of the instrument.

The applicator portion of the gingival mar- H ginal trimmer shown in Fig. 2 includes a cutting edge I! and a ledge [B which meet in an obtuse angle therebetween. The cutting edge I? includes approximately two-thirds of the Width of the applicator portion of the instrument, whereas the ledge includes the remaining one-third of the width of this portion. The upper end of the cutting edge I! is rounded so as to eliminate a sharp point at the tip thereof which might irritate the tissue.

The cutting edge ll is beveled to a sharp edge [9 and the ledge I8 is a flat surface. As illustrated in Fig. 1, the cutting edge ll is vertical when the instrument handle I0 is held in a vertical position; however, the angle may be varied as desired to obtain the angle of bevel desired in the tooth.

In use, the fiat ledge portion I8 is maintained in a horizontal position as shown in Fig. 4, resting on the flat surface 26 of the tooth. This positioning of the ledge portion l8 results in the cutting edge being placed on the margin in its proper cutting position. The dentist is thus able to feel the actual margin of the tooth in the notch-like portion of the instrument without Watching it.

By maintaining the instrument steadily against the corner of the gingival margin and manipulating it, the cutting edge cuts the desired bevel similar to that shown in Fig. 6 with the ledge acting as a guide for the cutting edge.

Utilizin this instrument, a stability of control is allowed that results in a bevel of predetermined width and depth. Utilizing the instruments in current usage, no stability is allowed to the instruments and the resulting bevel is usually very uneven, or in some cases the whole shoulder disappears into a lay bevel, as is shown in Fig. 7. This is not a desirable bevel.

Finally, slippage from the tooth into the gum is eliminatdby use of this invention,thus eliminating bleeding and damage.

It should be understood that this invention applies equally well to other types of working" and said ledge meet in an obtuse angle, whereby surfaces than the cuttin edge shown thatareused in gingival marginal preparation, as well as to other instruments with a similar cutting "edge" #1 which could utilize a ledge for control purposes A filing surface useful in gingival marginal preparation utilizing the present invention is'--shoWn=- in Fig. 3.

It shouldbe 'further-understood that any type of handlec'an be substitu-ted'for'the handle illustrated, and the angle between the applicator portionr of the instrument and the handle can be.

varied as required: I *It is' further: contemplated that both ends of the handle can be supplied with applicator portionss It .will 'be obvioustothose" skilled-in the art that various changes may be made'without' departing from the spirit-of the invention and the inventioni's not limited to what is shown-inthe drawings and "described 'in the specification; but i only aspindicatedin the appended claims.

What isclaimed is-rr- 1. Af-dental instrument;comprising-a handle,

and anapplicator portion projeeting'therefrom,

said-ledgeacts as a guide during the use of said cutting edge.

5. A"=de'ntal instrument in accordance with claim-4, wherein said cutting edge is a beveled surface.

6. A dental instrument in accordance with claim 4, wherein said cutting edge includes more than 'one-half of the width-of sa-id applicator portion.-

7. A dental instrument, comprising a handle, and an applicator portion projecting therefrom, said applicator portionhaving a-cutting edge and a flat ledge thereon;w:herein said'cutting edge is abeveled surface,"whereby saidiedge-acts as a guide during the use of said :cutting edge.

8. A dental instrument in accordance U with claim 7, wherein said cutting edge-and said-ledge meet in an Qbtuse'angIeJ 9. A dental instrumenficomprising a: handle; and an applicator portion projecting therefrom, said applicator portion having a fiat ledge there on and a filing surface' adjacent "to: said :ledgep wherein said filing surfa'ce and said ledge meet' in an obtuse'anglegwhereby'saiti le'd'ge acts as a guide during the use of said filing surface:v

JACK DIE NERL 4i References-Cited'in the file of this patent FOREIGN PATENT'S Number v Country Date H ,'260,14 7.- Italy ("mm-Ash; Sept.'7,:1928 

